@Fix some warnings when compiling in maintainer-mode (Stig)

@Fix some warnings when compiling in maintainer-mode (Stig)
@Made mysql and gd work as shared extensions again (Stig)
- Fixed some warnings in maintainer-mode.
- Made mysql and gd work as shared extensions again by defining
  COMPILE_DL if PIC is defined.
# We need a better solution for building .so extensions than this
# PIC/COMPILE_DL hack!